DY 
A FISH BRAIN FROM THE COAL MEASURES 143 
tions of the lobes in the Coal Measures fish. There is no indi- 
cation of the structure which, in the Coal Measures fish, has 
been interpreted as a median encephalic vein (at first interpreted 
as a pineal body). In the region just posterior to the lateral 
cerebellar lobes there is considerable difference in the structure 
of the brains. In the Mississippian fish there are four distinct 
elevations, the most anterior two of which may be interpreted as 
non-involuted portions of the cerebellum (fig. 4), though it is 
much more probable that they are the anterior portions of the 
tuberculum acusticum. There is a well marked median sulcus 
between the two elevations, a continuation of the sulcus divid- 
ing the lateral lobes of the cerebellum. There is no indication 
of the tubular elevation as seen in the Coal Measures fish. 
Just posterior to these two lobes and divided from them by a 
slight transverse sulcus lie two smaller lobes, similar in general 
appearance to the anterior ones which have been interpreted as 
anterior lobes of the tuberculum acusticum. These posterior 
lobes are tentatively interpreted as posterior portions of the 
tuberculum acusticum. It is unfortunate that the posterior 
portion of the brain is lost and it is to be hoped that Doctor 
Eastman will illustrate this portion of the anatomy for us from 
the additional material in his possession. The vertical semi- 
circular canals follow the same course in the two forms and have 
the same relations. <A lateral portion of the ear of the Mississip- 
pian fish is preserved, which I suppose is the ampulla of the hori- 
zontal semicircular canal. It is present on both sides of the 
brain (fig. 4) and, if it is correctly imterpreted, the ampulla 
lies much more lateral in the Mississippian than in the Coal 
Measures brain. 
The specimens studied by Eastman were submitted to Parker 
(08) who studied them and corroborated Eastman’s obser- 
vations as follows: ‘‘On the right-hand side the anterior vertical 
canal is well preserved throughout its whole extent from the 
apex of the superior sinus of the utriculus to the anterior ampulla. 
Doctor Parker was especially interested in the ear as preserved 
in the several nodules submitted to him and the greater part of 
his discussion is devoted to this organ. He also discusses the 
